1. Technical Field
The present invention relates to an image processing method, a program for image processing, and an image processing apparatus.
2. Related Art
In the technical field to which the present invention pertains, a technique for reducing the processing load of gradation drawing has been proposed. For example, JP-A-11-25282 discloses an image processing technique for reducing processing load for the plotting of gradation through the following procedures. A gradation generating part uses a vector in the direction of change of a transferred color and the information of colors at the start and end points, and sets plural adjacent band-shaped areas vertical to a straight line connecting the start point with the end point whose inside color values are made uniform, and finds a cross point between the boundary of the band-shaped area and a scanning line as the changing point of color. The changing point of the color and a color between the changing points are sequentially found for each scanning line so that the gradation pattern of the scanning direction can be formed. The related-art image processing technique described in JP-A-11-25282 makes it possible to reduce the processing load of gradation drawing through the procedures explained above.
However, a method for color arrangement in the band-shaped areas is not considered in the related-art image processing technique described in JP-A-11-25282. For this reason, for example, when color arrangement is performed for each pixel in a designated target gradation area, there might occur processing overload for the plotting of gradation, which depends on the number of pixels that are arrayed between a start point and an end point and/or the number of colors therebetween. In addition, the related-art image processing technique described in JP-A-11-25282 has another disadvantage in that some displacement (i.e., shift) might occur in the changing point of color for pixels depending on, for example, the angle of gradation inclination. In such a case, it is practically impossible or at best difficult to achieve gradual gradation (i.e., smooth gradation).